I've always believed that the best Champagnes are the small producers, the names that you don't recognize. Forget the Veuve, Krug, Moet..........they're huge brands and all, but I firmly believe that they overprice, without the corresponding levels of quality. That's just my thought, but the more Champagne I drink, the more I feel that this is true.
I recently opened a bottle of Champagne Chapuy, Grand Cru Blanc de Blancs. A lovely wine, lots of complexity in the nose, with an incredibly intense flavour profile in the mouth. Very focussed and precise - this is not a sipping wine. It went beautifully with foods that were quite rich. A long, long finish, just a gorgeous wine.
Buy based on taste. Don't buy on fame or name brands. The luxury labels are great, but there are better ways to waste your money.